COMMERCIAL IMAGE - In this photograph taken by AP Images for BlackBerry, BlackBerry fans take photos during an ugly sweater holiday party hosted by BlackBerry, Wednesday, Dec. 21, 2011, in New York. BlackBerry debuted the Ugly Sweater App and Angry Birds App at the event. (Diane Bondareff/AP Images for BlackBerry)

Emily Bell shows off her ugly Christmas sweater and vest combination in her home Thursday, Dec. 22, 2011, in St. Francis, Wis. (AP Photo/Morry Gash)

In this picture taken Dec. 21, 2011, Jack McCarthy, 17, poses with some sweaters in Wauwatosa, Wis. McCarthy, 17, launched UltimateUglyChristmas.com with his 22-year-old sister last month, and he expects to clear $5,000 in profit this year. They got their inventory by scavenging items from thrift stores and yard sales. (AP Photo/Carrie Antlfinger)

COMMERCIAL IMAGE - In this photograph taken by AP Images for BlackBerry, Super Bowl Champion and NFL studio analyst Michael Strahan, center, poses with fans Steve Mertz, left, and Josh Mertz, both of Allentown, Penn., at an ugly sweater holiday party hosted by BlackBerry, Wednesday, Dec. 21, 2011, in New York. BlackBerry debuted the Ugly Sweater App and Angry Birds App at the event. (Diane Bondareff/AP Images for BlackBerry)

MILWAUKEE — Oh, the sweater designs are frightful, but the parties are so delightful. So if you’ve got one to wear, let it show, let it show, let it show.

If your grandmother ever gave you a cheesy holiday sweater you never thought you’d wear, be grateful — it’s a hot fashion item now. Gaudy Christmas sweaters have become all the rage. Ugly-Christmas-sweater parties are so popular that thrift stores and specialty retailers are making sure the kitschy clothing is in stock, and enterprising entrepreneurs are cashing in.

One Chicago couple say they’ve sold more than 3,000 sweaters this year from a website they started in 2008, while a pair of Milwaukee siblings expect to clear a $5,000 profit from a new site they launched just last month.

Jack McCarthy, 17, and his sister sell sweaters scavenged from thrift stores and yard sales for anywhere from $19 to $45 on UltimateUglyChristmas.com.

“People just seem to love outdoing each other in ugliness,” McCarthy said. “The key is, you want something that’s tacky in a good way. You don’t want ugly like boring, you want something like a piece of art. Something that might look good if it weren’t on a sweater.

“Like it might be a good Christmas decoration, but once you put it on yourself that’s where it becomes ugly.”

The sweaters’ popularity reflects a common fashion arc: Something trendy goes out of style, only to become cool again decades later. Some people speculate that loud sweaters evoke fond memories of holidays past. Others say it’s just an expression of holiday cheer.

Either way, when it comes to Christmas sweaters, uglier is better.

Bright and mismatched colors are a plus, as are sequins, beads and fringes. But the clincher is graphics — winter scenes busy and intricate enough to make the viewer cringe.

Emily Bell knows ugly when she sees it. The 30-year-old from the Milwaukee suburb of St. Francis was determined to win her friend’s ugly-sweater contest. So she scoured thrift stores with one strategy: If a garment could be called tasteful, it wasn’t good enough.

For less than $10 she bought a blue blazer covered in oversized stars, trees and snowmen, along with a bright red sweater showing a Christmas tree trimmed with bulbous red ornaments.

“Everyone was horrified and amused,” Bell said of partygoers who awarded her the top prize. “Either piece is ugly on its own, but there’s no one on Earth who could see them together and find them anything but ugly.”

Retailers are capitalizing on the demand.

Lisa Ritter, director of marketing for Goodwill in St. Paul, Minn., credited a promotion with helping the thrift store’s Twin Cities locations sell hundreds of ugly Christmas sweaters this year.

“There’s only one place that got a complaint, a store in a smaller community,” she said. “It was mostly people who were offended because we were making fun of a clothing item that they wear, and wear proudly.”

Ugly is certainly in the eye of the beholder.

Jennifer Rogalin manages Ragstock, a specialty-clothing store in Madison. She said a lot of their holiday items are actually attractive, but so many people ask for ugly sweaters that the store now advertises them that way.

“Sometimes I’ll be helping someone who wants something ugly,” she said. “They’ll pick one and I’ll say, ‘Oh, I thought that was cute.’ And they’ll say, ‘Really? I thought it was hideous.’”

Ritter suggested the ugly-sweater craze gets a boost from social media, as more people tweet about ugly-sweater parties and post the pictures on Facebook. Indeed, “ugly sweaters” has been a popular trend on Twitter this week.

Some predict the movement will only get bigger.

Clarissa Trujillo, 30, said her husband’s company had an ugly-sweater party in 2007, but the couple couldn’t find a sufficient ensemble. So they launched UglySweaterStore.com the next year and business took off. Sales grew from about 500 sweaters in 2008 to more than 3,000 this year, Trujillo said.

“I knew we were on the verge of a growing trend, but I can’t tell you how insane it’s been since then,” she said. “Ugly sweaters are huge.”